// Formatting library for C++ - std::ostream support
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.

#ifndef FMT_OSTREAM_H_
#define FMT_OSTREAM_H_

#include <fstream>
#include <ostream>
#if defined(_WIN32) && defined(__GLIBCXX__)
#include <ext/stdio_filebuf.h>
#include <ext/stdio_sync_filebuf.h>
#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
#include <__std_stream>
#endif

#include "format.h"

FMT_BEGIN_NAMESPACE

template <typename OutputIt, typename Char> class basic_printf_context;

namespace detail {

// Checks if T has a user-defined operator<<.
template <typename T, typename Char, typename Enable = void> class is_streamable
{
private:
    template <typename U> static auto test(int) -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>() << std::declval<U>()) != 0>;

    template <typename> static auto test(...) -> std::false_type;

    using result = decltype(test<T>(0));

public:
    is_streamable() = default;

    static const bool value = result::value;
};

// Formatting of built-in types and arrays is intentionally disabled because
// it's handled by standard (non-ostream) formatters.
template <typename T, typename Char>
struct is_streamable<T,
                     Char,
                     enable_if_t<std::is_arithmetic<T>::value || std::is_array<T>::value || std::is_pointer<T>::value || std::is_same<T, char8_type>::value ||
                                 std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<T, std_string_view<Char>>::value ||
                                 (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>> : std::false_type
{
};

// Generate a unique explicit instantion in every translation unit using a tag
// type in an anonymous namespace.
namespace {
    struct file_access_tag
    {
    };
}  // namespace
template <class Tag, class BufType, FILE* BufType::*FileMemberPtr> class file_access
{
    friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
};

#if FMT_MSC_VERSION
template class file_access<file_access_tag, std::filebuf, &std::filebuf::_Myfile>;
auto get_file(std::filebuf&) -> FILE*;
#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
template class file_access<file_access_tag, std::__stdoutbuf<char>, &std::__stdoutbuf<char>::__file_>;
auto get_file(std::__stdoutbuf<char>&) -> FILE*;
#endif

inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data)
{
#if FMT_MSC_VERSION
    if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
        if (FILE* f = get_file(*buf))
            return write_console(f, data);
#elif defined(_WIN32) && defined(__GLIBCXX__)
    auto* rdbuf = os.rdbuf();
    FILE* c_file;
    if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
        c_file = fbuf->file();
    else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
        c_file = fbuf->file();
    else
        return false;
    if (c_file)
        return write_console(c_file, data);
#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
    if (auto* buf = dynamic_cast<std::__stdoutbuf<char>*>(os.rdbuf()))
        if (FILE* f = get_file(*buf))
            return write_console(f, data);
#else
    ignore_unused(os, data);
#endif
    return false;
}
inline bool write_ostream_unicode(std::wostream&, fmt::basic_string_view<wchar_t>) { return false; }

// Write the content of buf to os.
// It is a separate function rather than a part of vprint to simplify testing.
template <typename Char> void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf)
{
    const Char* buf_data = buf.data();
    using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
    unsigned_streamsize size = buf.size();
    unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
    do
    {
        unsigned_streamsize n = size <= max_size ? size : max_size;
        os.write(buf_data, static_cast<std::streamsize>(n));
        buf_data += n;
        size -= n;
    } while (size != 0);
}

template <typename Char, typename T> void format_value(buffer<Char>& buf, const T& value, locale_ref loc = locale_ref())
{
    auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
    auto&& output = std::basic_ostream<Char>(&format_buf);
#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
    if (loc)
        output.imbue(loc.get<std::locale>());
#endif
    output << value;
    output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
}

template <typename T> struct streamed_view
{
    const T& value;
};

}  // namespace detail

// Formats an object of type T that has an overloaded ostream operator<<.
template <typename Char> struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char>
{
    void set_debug_format() = delete;

    template <typename T, typename OutputIt> auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const -> OutputIt
    {
        auto buffer = basic_memory_buffer<Char>();
        format_value(buffer, value, ctx.locale());
        return formatter<basic_string_view<Char>, Char>::format({buffer.data(), buffer.size()}, ctx);
    }
};

using ostream_formatter = basic_ostream_formatter<char>;

template <typename T, typename Char> struct formatter<detail::streamed_view<T>, Char> : basic_ostream_formatter<Char>
{
    template <typename OutputIt> auto format(detail::streamed_view<T> view, basic_format_context<OutputIt, Char>& ctx) const -> OutputIt
    {
        return basic_ostream_formatter<Char>::format(view.value, ctx);
    }
};

/**
  \rst
  Returns a view that formats `value` via an ostream ``operator<<``.

  **Example**::

    fmt::print("Current thread id: {}\n",
               fmt::streamed(std::this_thread::get_id()));
  \endrst
 */
template <typename T> auto streamed(const T& value) -> detail::streamed_view<T> { return {value}; }

namespace detail {

// Formats an object of type T that has an overloaded ostream operator<<.
template <typename T, typename Char> struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>> : basic_ostream_formatter<Char>
{
    using basic_ostream_formatter<Char>::format;
};

inline void vprint_directly(std::ostream& os, string_view format_str, format_args args)
{
    auto buffer = memory_buffer();
    detail::vformat_to(buffer, format_str, args);
    detail::write_buffer(os, buffer);
}

}  // namespace detail

FMT_MODULE_EXPORT template <typename Char>
void vprint(std::basic_ostream<Char>& os, basic_string_view<type_identity_t<Char>> format_str, basic_format_args<buffer_context<type_identity_t<Char>>> args)
{
    auto buffer = basic_memory_buffer<Char>();
    detail::vformat_to(buffer, format_str, args);
    if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()}))
        return;
    detail::write_buffer(os, buffer);
}

/**
  \rst
  Prints formatted data to the stream *os*.

  **Example**::

    fmt::print(cerr, "Don't {}!", "panic");
  \endrst
 */
FMT_MODULE_EXPORT template <typename... T> void print(std::ostream& os, format_string<T...> fmt, T&&... args)
{
    const auto& vargs = fmt::make_format_args(args...);
    if (detail::is_utf8())
        vprint(os, fmt, vargs);
    else
        detail::vprint_directly(os, fmt, vargs);
}

FMT_MODULE_EXPORT
template <typename... Args> void print(std::wostream& os, basic_format_string<wchar_t, type_identity_t<Args>...> fmt, Args&&... args)
{
    vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
}

FMT_END_NAMESPACE

#endif  // FMT_OSTREAM_H_
